Aws EC2 Key File Workaround

This repository contains information on how to regain access to an EC2 instance in the event that the key file is lost.

The simplest way is to create a AMI of the instance and creating a new instance with a new key using the AMI

the following a way to do in the Production Env

Steps

Consider Having a Ubuntu instance called Instance-A and you have lost its key (.pem file)

• create a new instance with same region and VPC as of the lost pem file instance. Name it as helper instance and create a new Key file for this (helperkey.pem).

• Now stop the Instance-A file instance. Remember not to terminate instance but to stop it

• Go to EBS volumes, select the root volume of the Instance-A and detach.

• Attach the Instance-A volume to the helper (sdf) instance

• Now start and Login to the helper instance and Mount the Attached Volume to a Folder in the Root volume

check for the attached volume

lsblk

Mount it

mkdir /mnt/root-vol
mount /dev/xvdf1 /mnt/root-vol

check it

df -h

• Copy the SSH auth keys to the attached Volume

  cat /home/ubuntu/.ssh/authorized_keys >> /mnt/root-vol/home/ubuntu/.ssh/authorized_keys

unmount it

umount /mnt/root-vol/

• Now Detach this attached volume and re-attach to the Instance-A

• Now login with the helper key